1. Field of the Invention
The present invention relates to an anti-theft system for construction machines and a method for managing construction machines.
2. Description of the Related Art
For example, in an anti-theft system for construction machines disclosed in Japanese Patent Publication Laid Open No. 73411/2000, ID or identification information intrinsic to a construction machine is allocated to the construction machine, and only when a key (hereinafter referred to as “ID key”) having ID information matching the said ID information is inserted into a key box, the construction machine can be operated.
If the ID key differs for each construction machine, for example a rental trader who manages a large number of construction machines must carry about ID keys in a number corresponding to the number of the construction machines. This is inconvenient.
If ID information is made rewritable easily as a measure against the loss of ID key, it is likely that a person other than the owner of a construction machine may rewrite ID information erroneously or a thief may rewrite ID information and steal a construction machine.
Further, when consideration is given to the application side of the construction machine rental business, for example in the case where a single construction machine is used by plural operators by turns, plural ID keys must be provided to the operators at the time of renting the construction machine. In this case, with only the ID key for rent and a spare ID key which the rental trader keeps, there occurs a deficiency in the number of the keys.